Suction devices are used in many medical applications to draw various fluids from the patient area and to store the fluids for later use or disposal. Suction devices have been utilized to draw aspirated fluids from a patient during a surgical operation and during the post-operative period. Suction devices are also used to drain fluids from the gastrointestinal tract, as well as to drain pulmonary mucous in tracheal incisions, and the like. Suction sources may be fixed or mobile. The fixed systems comprise wall vacuum outlets connected to a central system. The mobile systems are either relatively large capacity devices which are bulky or portable systems. Portable suction sources operate on power supplied by either electricity, compressed gas or manual power and may be used in a hospital, ambulance, home, or in the field. A summary of the state-of-the-art in portable suction devices is set forth in Health Devices, March 1978, page 11 and pages 120-141.
In emergency conditions, such as in battlefield operations, it would be extremely desirable to have a portable suction device capable of continuous operation in any orientation. The known prior art suction collection systems are incapable of operation if the collection container tips over and falls in a sideways or upside-down position. Additionally, most prior art portable suction devices are calibrated for vacuum levels at one location and must be recalibrated if operated at different altitudes. Accordingly, a need exists for a relatively lightweight portable suction system capable of delivering regulated suction of precise vacuum and precise flow rate, which is capable of continuous operation in any orientation of the system.